The purpose of this program is to expand the US-China Collaborative, Population-Based Surveillance and Research Program or Maternal-Child and Family Health, which represents a significant effort to build upon existing infrastructure for population-based surveillance and other research activities established by previous collaborative work between HHS/CDC and the Peking University Health Sciences Center (PUHSC). This program will use China's unique demographic, public-health and data infrastructure to address questions for which data are not currently available in the United States or anywhere else in the world. In addition, the unique attributes of the long collaboration between HHS/CDC and PUHSC would be almost impossible to replicate.